1. Field of the Invention
The present invention relates to an apparatus for coupling an optical member, such as color-separating prism, with a lens unit.
2. Description of the Prior Art
In broadcasting television cameras and the like, a zoom lens is often used as their taking lens. This zoom lens is attached to the main body of an optical apparatus (camera main body) as a zoom lens unit comprising a lens mount in which the zoom lens is accommodated. In order to selectively use various kinds of zoom lenses depending on states of taking, a lens mount structure configured so as to detachably attach the lens unit to the main body is widely employed as well.
Used in such a lens mount structure is an optical member coupling apparatus in which a mechanism for detachably holding the lens unit is attached to one surface of a flat panel, while a color-separating prism for separating an incident luminous flux into three primary color light components of R (red), G (green), and B (blue) is attached to the other surface. In order to couple the lens unit and the color-separating prism together by means of such an optical member coupling apparatus, the color-separating prism is initially secured to the panel, then a reference lens having a fixed reference distance between its mounting surface and the imaging surface of a CCD disposed downstream the color-separating prism is attached to the panel, and thereafter the CCD is attached to the rear end face of the color-separating prism so that the optical axis of the reference lens aligns with the imaging center.
Though the CCD is attached such that its imaging center aligns with the optical axis of the reference lens; when various kinds of lens units are exchanged for use as mentioned above, the optical axis of the lens unit and the imaging center of the CCD may deviate from each other due to an error in designing or the like. When the optical axis of the lens unit and the imaging center of the CCD thus deviate from each other, pictures taken by the CCD may erroneously shift.